CYP3A4, a cytochrome P450, is an important phase-I drug metabolizing enzyme which has been shown to vary up to 10-fold in normal healthy individuals. The purpose of this study is to determine the effect that commonly used medications and substances found in a typical American diet such as indoles, charbroiled foods, and flavenoids may have on the expression of CYP3A4 in the human small bowel and colon.